JPH0214749A - Method and apparatus for regenerating fluidized bed of catalyst - Google Patents

Abstract

PURPOSE: To optimize temperature of a regeneration chamber by burning a portion of cokes in a fluidized bed regeneration first chamber and introducing catalyst particles regenerated at this time into a fluid containing oxygen substantially in a countercurrent. CONSTITUTION: The 50-90% cokes is burned with a countercurrent of air jetted into a bottom of a generator. The combustion gas rich in CO and H2 O free from the catalyst powder in a cyclone is discharged from a line 22. Next, partially regenerated catalyst particles are transported into a second regeneration chamber 23 at the upper part of the first chamber through a pipe 24 fed with air from a line 25. A diffuser 26 fed with air from the line 25 is disposed at the bottom of the second chamber 23. Fluidization of the particles of part of the regenerated catalyst is adjusted by an annular diffuser 28 in a buffer casing 27.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fluidized bed catalyst regeneration method and an apparatus for implementing this method. In particular, the present invention relates to the fluidized bed regeneration of a submerged catalyst of hydrocarbon residue and coke as a result of reaction with a hydrocarbon charge. Specifically, the present invention relates to a regeneration treatment of a hydrotreating catalyst, a cracking catalyst, a reforming hydrocracking catalyst, or a regeneration treatment of a contact material for pyrolysis.

[Prior Art and Intermediate Point] As is well known, in the petroleum industry, a cranking process is generally used to split high molecular weight and high boiling point hydrocarbon molecules into small molecules with a low boiling point suitable for the application, and catalysts are generally used in the petroleum industry. is used.

A method currently also used for this purpose is the so-called catalytic cranking method in the fluidized state (in English, Flui
d Catalytie Cracking, or FCC method). In this type of process, a hydrocarbon charge is vaporized by high temperature contact with a cranking catalyst which is held in suspension by the vapor of this charge.
After the desired molecular weight has been reached by cranking and the boiling point has shown a corresponding decrease, the catalyst is separated from the product.

In this type of process, the desired boiling point reduction results from controlled catalytic and thermal reactions. These reactions occur almost instantaneously when the charge is vaporized and brought into contact with the catalyst. However, while the catalyst is in contact with the charge, as a result of hydrocarbon adsorption and coke deposition on the active sites,
Rapidly inactivates. This deactivated catalyst is therefore continuously stripped, e.g. by steam, of the adsorbed hydrocarbons or entrained hydrocarbons, and then, e.g. in one or more stages of regeneration zone, the adsorbed coke or carbon It is necessary to continuously activate the catalyst by controlled combustion of hydrogen without changing its properties, and to circulate this regenerated catalyst to the reaction zone. Combustion air is injected at the bottom of the regenerator, and a cyclone is provided at the top to separate the combustion gases from entrained catalyst particles. The catalyst thus regenerated is generally discharged from the bottom of the regenerator and then circulated to the bottom of the elevator or "riser" to generate the cranking reaction.

Naturally, this FCC method is carried out so that the reaction zone is in thermal equilibrium. In other words, the feed rate of regenerated hot catalyst must be adapted to the various thermal requirements of a reaction section. In particular, it must be possible to accommodate the preheating of the liquid charge, the evaporation of this charge, the addition of the heat required by the overall endothermic reaction, and the heat losses of the system.

The amount of coke deposited on the catalyst and the method of its regeneration determines the final temperature reached by the catalyst in the regeneration zone. This is because the heat generated from combustion is used to reheat the air, combustion gases, and catalyst particles. The amount of coke produced in the cranking unit in operation is therefore essentially constant, provided that the thermal balance is not changed by external influences.

More specifically, when carrying out catalytic cranking of high boiling point (generally above 550°C) hydrocarbon charges or charges with high Conradson carbon content and high metal concentrations, a large amount of coke is deposited on the catalyst. Heavy hydrocarbons are deposited. The combustion during the catalyst regeneration process then releases a large amount of heat, which not only exceeds the metallurgical limits of the equipment;
This causes deactivation of the catalyst from the viewpoint of the catalyst environment (wetting rate 1 contamination rate with heavy metals, alkali metals, etc.).

In order to limit these drawbacks, the prior art has proposed a method to first limit the regeneration temperature to 750°C or less by placing a heat exchanger in the regeneration chamber, thereby suppressing excessive coke production. It was done. In this case, the decrease in temperature is determined by the catalyst mass ratio to the charge (generally the "C10 ratio").
is compensated for by an increase in However, this method suffers from excessive production of coke which impairs the added value of the charge due to a reduction in bed weight, which also leads to oversizing of the regenerator and ancillary equipment, and which results in exhaust gases enriched in NOx and SOx. Generates smoke.

The regenerator is then divided into two zones, where all or part of the combustion occurs in co-current conditions of catalyst and oxidizing fluid (e.g., U.S. Pat. No. 4,035,284 and French Patent No. 2,
186,291), at relatively high temperatures, but 75
Methods have been proposed in which the residence time of the catalyst at temperatures not exceeding 0° C. is minimized so as not to reduce the activity of the catalyst. However, in both of the above cases, the regeneration temperature is limited by the fact that the combustion gas contains water vapor resulting from the combustion or stripping process of the heavy hydrocarbons contained in the coke. At temperatures above 730-750°C the presence of water vapor is prohibited. This is evident from the behavior of metal oxides in this temperature range, especially vanadium oxide in the presence of sodium.

Therefore, the method of jI3 (see US Pat. No. 4,332,674 and French Patent No. 2,188,291)
In the first stage of the regeneration process, in a chamber with its own exhaust gas system, the active sites of the catalyst are not destroyed by the water vapor resulting from the stripping stage or from the combustion of the hydrocarbons remaining in the coke on the catalyst. The catalyst is maintained at a temperature below a maximum of about 700° C. to cause intermediate temperature incineration of only a portion of the coke and hydrocarbons deposited on the catalyst. Such temperature limitations in the first regeneration stage keep the amount of combustion air below the stoichiometric amount to reduce carbon to CO
This is achieved by combustion to CO2, preferably CO2. Next, in the second stage,
In the second chamber, which is different from said chamber, the water vapor has been removed beforehand, so that the complete combustion of the carbon remaining on the catalyst is no longer limited in terms of temperature. This second
In the step, more than the stoichiometric amount of oxygen is used to promote combustion to CO□, so the temperature is reduced to thermal equilibrium (
in some cases up to 950°C). However, in this case, taking into account the metallurgical constraints of the device, e.g. the cyclone and the catalyst discharge vessel are placed outside the combustion zone,
Metal parts in the combustion area must be protected by internal refractory material.

Therefore, in order to regenerate a highly coked catalyst at high temperatures, it is preferable to carry out the combustion in two separate zones, each with an exhaust gas system, so that the catalyst regenerated in this way is no longer in the 1 regeneration stage, i.e. 30-70% of the deposited coke is below 700 °C, preferably 650 °C in the first regeneration stage.
The 30~
70% of the carbon is combusted in a fluidized bed in a second stage without temperature restrictions or discharged from a second regenerator.

Although this method is carried out at a regeneration temperature in a second regeneration chamber of 750-950° C. depending on the intended purpose or the type of charge to be treated, it still has drawbacks.

That is, regeneration temperatures may be too high resulting in overly rapid deactivation of certain catalysts, resulting in reduced efficiency, or thermal catalyst circulation below the theoretically desired level for optimal conversion. arise.

It is therefore preferable to use multiple heat exchangers to limit the temperature of each regenerator, but this involves increased costs and difficulties in regulating the temperature of each chamber.

OBJECTS AND EFFECTS OF THE INVENTION The present invention provides a simple method for optimizing the temperature in the two regeneration chambers and adapting the final temperature of the regenerated catalyst to the requirements of the feedstock processed in the conversion unit. We are here to provide you with a method.

SUMMARY OF THE INVENTION The main object of the present invention is a method for continuously regenerating a catalyst by fluidized bed combustion of coke deposited on the catalyst during a hydrocarbon conversion reaction, the method comprising:
As a first step, in a fluidized bed type first regeneration chamber,
The catalyst particles to be combusted at a temperature T1 below about 730° C., preferably between 650 and 710° C., are introduced substantially countercurrently to the oxygen-containing fluid, and the first regeneration chamber is 10 to 50% of the remaining amount of coke is removed as a second stage in a second regeneration chamber spaced from the first regeneration chamber. , in the continuous catalyst regeneration method, the catalyst is combusted at a temperature T2 higher than said temperature T1 and <950°C, preferably 910°C, in the presence of a fluid containing oxygen in an amount greater than the stoichiometric amount of combustion; The temperature T2 of the regenerated catalyst particles exiting the chamber and being circulated to the conversion reaction zone is such that a controlled amount is taken from the catalyst in this second regeneration chamber and brought to a temperature T3 below T1.
and introducing this cooled catalyst part into the fluidized bed of a first regeneration chamber, the combustion temperature of said first regeneration chamber is maintained at a defined temperature value corresponding to the needs of the reaction zone. By appropriately changing the amount of oxygen-containing fluid introduced into this chamber, the value of TI
The purpose of the present invention is to provide a method for continuously regenerating a catalyst that is maintained at a constant temperature.

The method of the present invention increases the combustion of coke by increasing the oxygen flow rate in the first regeneration chamber, thus increasing the amount of heat generated and introducing the cooled catalyst in the heat exchanger.
It is possible to compensate for the cooling caused by C and maintain the temperature T1 in the first regeneration chamber at an optimal value close to 710°C, and it is also possible to transfer the catalyst with a low coke content into the second regeneration chamber. Make it. In this way, the final temperature T2 as a result of complete combustion of the coke due to the presence of excess oxygen
can be lowered.

Excess oxygen in the second regeneration chamber means a proportion of oxygen above the stoichiometric amount of the reaction that substantially converts carbon to carbon dioxide.

This two-step combination according to the method of the invention offers several advantages compared to conventional methods.

First, the regenerated catalyst can be adjusted to a temperature that corresponds to the needs of the converter. In particular, the evaporation of the injected charge and C
10 ratio (catalyst/charge ratio) can be optimized.

This regenerated catalyst temperature is therefore less dependent than in the prior art on the difference in the amount of coke on the catalyst at the entrance and exit of the regeneration zone (the so-called "delta coke"difference); It is determined to correspond only to the required amount of heat. The method of the invention therefore allows selection of an optimal mass ratio between catalyst and charge. This selection allows a high octane number to be obtained and an increased conversion of the charge. Additionally, diluting the deactivated catalyst of the first regeneration chamber with the at least partially regenerated catalyst coming from the second regeneration chamber results in combustion kinetics with fewer hot spots. As a result, the temperature becomes uniform, and in the presence of water vapor the catalyst reaches its limit stability temperature (approximately 710 °C to 710 °C depending on catalyst residence time and temperature).
750° C.), which can further increase the coke combustion rate (up to 90% or more) without exceeding the specified temperature T1 in the first regeneration chamber.

Furthermore, by limiting the high temperature residence time of the catalyst particles in the second regeneration chamber to a minimum (less amount of coke is burned in the second regeneration chamber), the dimensions of the regenerator and/or its accessories can be reduced. can be reduced,
It is also possible to reduce the possibility of catalyst deactivation.

Furthermore, there is less catalyst deactivation than in conventional converters, so catalyst loadings (depending on the metal content of the charge and regeneration jl), which varies depending on the final temperature of the catalyst, is reduced by a significant proportion (on the order of about 25-50%).
This saves operating costs for the cranking units used and makes it easier to maintain catalyst activity at the desired level.

Since the amount of catalyst added is significantly reduced in this way, the catalyst circulating through the cranking catalyst becomes much more homogeneous in terms of catalytic activity, resulting in a higher selectivity of the product (gasoline or gas oil as the case may be). and yields are improved, resulting in improved utilization of the cranking unit effluent.

Finally, as a result of the removal of a large part of the coke in the first stage, the dimensions of the equipment of the second regeneration chamber (catalyst introduction device, flue gas exhaust means and means for separating the regenerated catalyst) are reduced, thereby reducing the The manufacturing cost of ranking units can be significantly reduced.

More specifically, the method of the present invention can be carried out as follows.

a- introducing a catalyst to be regenerated and an oxygen-containing fluid into a first regeneration chamber and causing said fluid to flow countercurrently with said catalyst from bottom to top; b- in an upper part of said first regeneration chamber; Separate the gas effluent and take the partially regenerated catalyst at the bottom of the first chamber and send it into a second regeneration chamber where the second regenerated catalyst is heated at a higher temperature. carrying out a regeneration step; C- withdrawing a portion of the catalyst from the second chamber into a heat exchanger to cool the catalyst and extracting heat; and d- extracting heat from the heat exchanger. Stage Il! extracting the cooled catalyst and circulating it into the fluidized bed of said first regeneration chamber! .

The catalyst exiting the second regeneration chamber is allowed to flow by gravity from top to bottom through the heat exchanger.

The catalyst also moves from bottom to top in the heat exchanger in a dense fluidized bed, and then the cooled catalyst overflows from this heat exchanger and forms a dense fluidized bed in the first regeneration chamber. You can go inside.

In the latter embodiment, the catalyst is circulated through the heat exchanger (cooling zone) from bottom to top, so that the risk of encountering dead zones in the heat exchanger is minimized. Due to the rise of the catalyst,
Stagnation zones with reduced heat exchange are prevented, thus improving catalyst flow.

Furthermore, the overflow of the catalyst creates a nearly constant level in the heat exchanger, which increases the stability of the heat exchange and provides a constant heat exchange surface.

According to another feature of this embodiment of the invention, the circulation rate of the regenerated swallow catalyst in the heat exchanger is adjusted by introducing fluidizing gas from the fluidizing ring into the bottom of the heat exchanger. It's all about what you can do. This fluidizing fluid, preferably air, is generally 0.1-1 m/s, preferably 0.3-0.
It is introduced at a speed of 5 m/s.

Values in this range resulted in improved heat exchange efficiency.

According to another feature of this embodiment, before the hot catalyst is introduced into the heat exchanger from the second regeneration chamber, it flows from top to bottom through an elongated conduit to this heat exchanger and then flows into the heat exchanger. Pass through the semi-circular elbow area placed in front. Generally, by injecting a first injection fluid into this conduit, the density of the catalyst is maintained at a value corresponding to bubble-free fluidization. Generally 0.05 to 0.4 kg/s/'f#cross section m2, preferably 0.1 to 0.2 kg/s/m2 of tube cross section, is injected with the first ventilation fluid. This fluid is air, preferably water vapor. Each injection level can be spaced apart from each other by 0.5 to 2 m, preferably from 0.6 to I11+. However, since the catalyst density is greater than the density in the heat exchanger, the catalyst can be easily introduced into the heat exchanger.

According to another embodiment of the invention, the flow of catalyst into the heat exchanger can be regulated by means of a regulating valve arranged on the conduit upstream of the heat exchanger.

However, in embodiments that feed into the heat exchanger from the bottom up, this regulating valve is not used, and a 0.01-0.05 kg/s/12 section, preferably in the elbow area, at its lowest
The second ventilation fluid, especially air, can be injected at least 17 times, preferably with a flow rate in the range of 0.02-0.03 kg/s/m2 BFr.

In this embodiment, the catalyst exiting the heat exchanger can be discharged from the top of the heat exchanger, or alternatively from the top of the heat exchanger, preferably from above the maximally utilized internal heat exchange surface to the side. It can be discharged by means of a disposed discharge conduit.

The amount of catalyst cooled in the heat exchanger is generally greater than 150% by weight of the catalyst circulating in the first regeneration chamber. It has been observed that excellent regeneration efficiency is obtained using chilled catalyst amounts in the range of about 15-50% by weight.

The catalyst temperature exiting the second regeneration chamber is typically about 710-
Temperatures from 900°C to 400-700°C, preferably 45°C
The increase in the flow rate of oxidizing fluid introduced into this first regeneration chamber to compensate for the cooling by introducing the cooled catalyst into the first regeneration chamber is therefore , can be on the order of 1 to 50% of the required flow rate when no heat exchanger is used.

In the combustion conditions according to the invention, the Co/Coz ratio in the first regeneration chamber is generally in the range from 0.3 to 1.5, preferably from 0.5 to 1.3.

According to a particularly preferred embodiment of the invention, the catalyst leaving the second regeneration chamber is cooled by means of a tubular heat exchanger known per se, in which a cooling fluid,
For example, air, water, steam or a mixture of these fluids is circulated and the fluid is extracted at a temperature generally in the range from 300 to 750<0>C. Extraction at this temperature level is particularly desirable. This steam can be reused and its high temperature can improve the stripping conditions of the catalyst deactivated by the reaction and improve the hydrocarbon recovery rate.

As mentioned above, the temperature T2 of the second regeneration chamber can be adjusted by varying the flow rate of the catalyst particles circulating in the heat exchanger, for example using a slide valve, and in this way the temperature T2 of the regenerated catalyst can be adjusted. The temperature can be matched to the catalyst/cracking hydrocarbon ratio to optimize the hydrocarbon conversion reaction.

In addition to the amount of catalyst circulating in the heat exchanger, a temperature probe is also provided to determine the difference between the measured temperature in the first regeneration chamber and the specified temperature and to operate the means for supplying the oxidizing fluid to the first regeneration chamber. can be used to adjust the flow rate of the oxidizing fluid in the first regeneration chamber.

Catalysts that can be regenerated by the method of the invention are generally those described in the prior art (eg, US Pat. No. 4,405,445). These catalysts generally contain about 1.3% or more by weight of residual hydrocarbons and coke, and s,ooo~60
,000 ppm.

According to a particularly preferred embodiment of the invention, CO combustion inhibitors or coke combustion promoters are added by conventional impregnation techniques on the catalyst, for example EP 107,375, 120.
Alkaline earth metal compounds such as those described in No. 096 and No. 32,277 can be introduced.

These impregnating agents are used in an amount of 0.001 to 5% based on the weight of the catalyst particles.
%, preferably 0.1-2%.

It is also an object of the present invention to provide a device for continuously regenerating this deactivated catalyst by fluidized bed combustion of coke deposited on the catalyst during a hydrocarbon conversion reaction. a J1 regeneration chamber for burning the coke deposited on the first combustion chamber, the first combustion chamber having an inactivation catalyst inlet conduit, an oxygen-containing fluid supply means and a gas exhaust means; a regeneration chamber, the second regeneration chamber having a conduit for introducing partially regenerated catalyst from the first chamber, a second combustion fluid supply means, and means for separating combustion gases from the regenerated catalyst. a heat exchanger; each chamber further comprising means for measuring the combustion temperature of the fluidized bed;
means for withdrawing a portion of hot catalyst from the second regeneration chamber to maintain the combustion temperature in the second chamber equal to a first specified value of 950°C or less, preferably 910°C;

means for transferring the sampled hot catalyst portion to the heat exchanger for cooling; and means for discharging the cooled catalyst in the heat exchanger and introducing it into the first regeneration chamber. , the temperature in the first regeneration chamber is 730° C. or less;
and means for regulating the supply of combustion fluid controlled by temperature measuring means in said first regeneration chamber to maintain it at a second specified value, preferably in the range of 650 to 710°C. be.

Transfer means for the hot catalyst coming out of the second regeneration chamber supplies this catalyst to the top of the heat exchanger, where it flows by gravity inside the heat exchanger from top to bottom and, after cooling, from the bottom of the heat exchanger. It may be discharged towards the first regeneration chamber.

It is also possible for the transfer means to reach the lower inlet of the heat exchanger so that the catalyst flows through the heat exchanger from bottom to top in a fluidized bed.

In either case, it is desirable that the heat exchanger be provided with fluid diffusion means for maintaining the catalyst therein in a fluidized bed state.

The heat exchanger can be of a type known per se.

That is, the heat exchanger includes a vertically oriented tube grid structure, with catalyst circulating on the outside of the tubes and refrigerant circulating on the inside of the tubes. According to another embodiment, the regenerated hot catalyst is circulated inside the tube, and the refrigerant is circulated outside the tube.

Heat exchangers can also be of other types. That is,
The partition walls forming the outer skin of the heat exchanger form part of the heat exchange surface, which is formed in the shape of a diaphragm tube and has a plurality of walls arranged concentrically with each other and parallel to the axis of the heat exchanger. The coolant circulation tubes are interconnected by longitudinally welded ribs to form a continuous outer surface that is pressure tight.

If the heat exchange surface is insufficient to guarantee the required heat exchange, a plurality of heat exchange tubes arranged regularly along at least one concentric circle are provided inside the heat exchanger.

These additional heat exchange surfaces are immersed in the fluidized bed, and these additional heat exchange surfaces can be diaphragm tube networks or tube bundles of various shapes (U-shaped, pin-shaped, or bayonet-shaped) or corrugated tubes. Consisted of.

An internal collector ensures water distribution and collects water from water vapor.

This diaphragm tube heat exchanger structure exhibits the following advantages:

Increasing the heat exchange surface for a given heat exchange volume or decreasing the internal heat exchange surface for a given total heat exchange surface. This promotes fluidization of the catalyst inside the heat exchanger and thus prevents the risk of dead zones or condensation zones occurring, which improves heat exchange.

- because the diaphragm temperature is so close to the temperature of the fluid circulating inside the tube that it does not require protection;
No internal heat resistance mechanism required.

The heat exchanger can be placed outside the regeneration unit, but can also be placed inside the first regeneration chamber, as described below. In this case, the heat exchanger is equipped with a partition wall of such height as to overflow the upper layer of the dense fluidized bed inside it. Further, it is preferable that the heat exchanger is provided with a fluid diffusion means for maintaining the catalyst in a fluidized state.

Control of the amount of hot catalyst withdrawn from the second regeneration chamber may be arranged, for example, downstream or upstream of the heat exchanger and said
It is carried out using a valve controlled by temperature measuring means in the regeneration chamber. This valve is opened as soon as the measured temperature exceeds the specified temperature.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

EXAMPLE In the illustrated apparatus, the catalyst is regenerated in a fluidized bed regenerator in which a second regeneration chamber is located above the ml regeneration chamber. This embodiment is of course not of a limiting nature.

The device shown in Fig. fi1 has a charge processed by an injector 2 connected to one feed line 3 from the bottom.

It comprises a column 1, a so-called charge elevator or "riser", which is supplied with regenerated catalyst through one conduit 4 and with fluidizing gas through one conduit 5 through a differential user 5'.

The riser 1 enters the casing 6 at its apex,
This casing is concentric with respect to the riser and in its interior the separation of the cracked charge and the stripping of the deactivated catalyst are carried out. The reaction products are separated in a cyclone 7, which is equipped at the top with a discharge pipe 8 for conveying the cracking charge to a fractionation unit 9, and inactivated catalyst particles are removed from this casing 6. stripped at the bottom. Therefore,
A conduit 10 supplies a stripping gas, generally water vapor, to differential users 11 arranged regularly in the lower part of the casing 6 .

The deactivated catalyst particles thus stripped are discharged through a conduit 13 into the first regeneration chamber 12, above which a regulating valve 14 is arranged. This conduit 13 terminates in an ejector for uniformly distributing the catalyst particles into the dilution section located above the dense fluidized bed 15 of the first chamber 12. The temperature of the fluidized bed is measured by a probe 16. If this temperature is reduced below a specified value T1 by the relatively cold catalyst introduced from line 17 as described below, the oxidation control fluid is sent by line 18 with regulating valve 19 to the differential user 20 at the bottom of the first chamber. is increased until the measured temperature 16 returns to the specified value.

Approximately 50-90% of the coke (and nearly all of the residual hydrocarbon compounds) is combusted by the countercurrent of air injected into the bottom of the regenerator in this manner.

CO and H2 from which catalyst powder was removed in cyclone 21
O-rich combustion gases exit line 22.

The partially regenerated catalyst particles are then transferred to a second regeneration chamber 23 above the first chamber by a conduit 24 supplied with air from line 25.

At the bottom of this second chamber, a differential user 26 is arranged which is supplied with air from line 25.

Some of the regenerated catalyst particles are attached to the buffer casing 27 on the side.
is discharged into the Inside this buffer casing,
Particle fluidization is regulated by an annular differential user 28 that is supplied with a fluidizing gas, such as air or an inert gas, from line 29 . The regenerated catalyst particles are fed from this buffer casing 27 via conduit 4 to the bottom of riser 1;
The amount is adjusted by opening and closing the valve 30. Above the regeneration chamber 23, the combustion gases are separated from the catalyst particles by a cyclone 31 and discharged by a line 32.

Another part of the regenerated catalyst is discharged by a conduit 33 into a heat exchanger 34 known per se, which heat exchanger 34 is connected to an inlet line 35 for a cooling fluid (generally air, water, or steam, alone or in a mixture). ) and a heated fluid discharge line 36 . The heat exchanger 34 is provided with a differential user 37 at its lower part, and this differential user is supplied with a fluidizing gas such as air through a line 38. This is achieved by maintaining good fluidization of the catalyst particles inside the heat exchanger.
This is to improve heat exchange. A valve 39, such as a slide valve, provided at the outlet of the heat exchanger 34 makes it possible to control the flow rate of catalyst transferred to the other chamber as soon as the regenerated catalyst temperature exceeds a specified value.

The temperature in the second regeneration chamber and thus ultimately the reaction zone 1
The amount of catalyst passing through the heat exchanger 34 is adjusted in order to maintain the introduction temperature into the cracker at a specified temperature suitable for the cracking charge. If the temperature of the catalyst to be regenerated is higher than this specified value, the amount of regenerated catalyst passing through the heat exchanger, 34 is increased. In that case, to compensate for the cooling of the fluidized bed catalyst in the first regeneration chamber, the amount of oxygen supplied is increased and the amount of coke burnt in the first chamber is increased. On the other hand, if the regenerated catalyst temperature is below the specified value necessary for good progress of the catalytic reaction, the amount of catalyst circulated into the heat exchanger 34 is reduced, and in some cases stopped. This allows the temperature of the regenerated catalyst to rise again.

The embodiment of FIG. 2 also includes a 1-inch reactor column called a charge elevator or "riser" fed with process charge by line 102 from the base, and at the bottom thereof from conduit 103 decomposition catalyst particles, For example, zeolite is introduced and fluidizing gas is introduced through line 132.

The riser 101 opens at its apex into a casing 104, which is concentric with respect to the riser and in which the separation of the cracked charge and the stripping of the deactivated catalyst are carried out. Implemented. The treated product is separated into a cyclone 105, the top of which is equipped with a cracking charge discharge pipe 106, and the spent and stripped catalyst particles are discharged from the bottom of this casing 104. be done. conduit 10
7 supplies a stripping gas, generally water vapor, to differential users 108 regularly arranged in the lower part of the casing 104.

The catalyst stripped in this way is transferred to the first regeneration unit 109a in the lower part of the casing 104 through a conduit 110.
A regulating valve 111 is provided on this conduit. This conduit terminates in a diffuser that uniformly disperses the catalyst particles above the dense fluidized bed 125 of the first regeneration unit 109a. The stripped catalyst particles are diluted and cooled in the lower part of the first regeneration unit by the addition of cooled catalyst particles. The cooled catalyst particles exit the second regeneration unit above the first regeneration unit and are transferred to a cooling means or heat exchanger 132 as described below.
catalyst particles cooled by A conduit 126a conveys the catalyst of the second regeneration unit to a separation well 127, at the bottom of which a fluidization ring 130 introduces air. This is to give the catalyst the correct density before it flows downwardly along the vertical conveying tube 128. Along this vertical tube 28, means for injecting a ventilation fluid, e.g.
' to hold.

A valve 131 located at the lower end of the vertical tube 128 and thus upstream of the heat exchanger controls the flow rate of hot regenerated catalyst fed to the lower end 133 of the heat exchanger 132. In order to regulate the catalyst flow rate into the heat exchanger, at least one ventilation fluid injection means 141 can be provided instead of said valve 131. Generally, this venting means is located in the intermediate elbow section 140, preferably at its lowest point.

A fluidization ring 134 that introduces and distributes air into the heat exchanger 132 causes the hot catalyst to rise through the heat exchanger, preferably in a dense fluidized bed. The heat exchange plates or tubes 135a making up the heat exchanger are completely immersed in the fluidized bed, and the level of catalyst in the heat exchanger is determined by the position of the discharge conduit 136. This discharge conduit 136 is located on the upper side of the heat exchanger, adjacent to the first regeneration unit 109a. The cooled catalyst becomes W due to overflow.
1 regeneration unit 109a and falls by gravity into a dilute fluidized bed above its dense fluidized bed 125.

A separation zone is created above the level of the dense fluidized bed of the heat exchanger, in which separation of the catalyst particles and at least a portion of the fluidizing or venting air is carried out.

This air is generally exhausted from the top 135 of the heat exchanger by conduits not shown, or can be circulated hot to all levels of the regeneration unit.

Inside the first regeneration unit, there is a line 11 at its bottom.
2 into the injector 113, 50 to 90% of the coke and almost the entire amount of residual hydrocarbons are combusted in a fluidized bed state. The catalyst particles are entrained by the combustion gases and separated by an internal cyclone 114 located at the top of the first regeneration bin. hydrogen sulfide,
The carbon dioxide and water rich combustion gases are discharged under pressure via line 115 and are post-treated, while the catalyst particles settle at the bottom of the first regeneration unit 109a. These particles are then transferred to conduit 116 through which air is introduced through line 117.
is transferred to the second reproduction unit 109b located above the first reproduction unit.

This second regeneration unit also has line 118 and injector 11.
Air is supplied by 9. Combustion of residual coke is carried out by countercurrent flow to the injection air.

Some of the regenerated catalyst particles are placed on the side of the buffer casing 12.
Ejected into 0. This flow rate of particles is normally controlled by an annular differential user 120 supplied with gas (inert gas or oxygen).
a, and these particles are further conditioned by conduit 103
through which the base of riser 101 is supplied by fluidizing gas injected from line 132. This conduit is kept vented. The combustion gases at the top of the second regeneration stage 1iW 109 b are treated in an internal or external cyclone 121, from the bottom of which the catalyst particles are returned through a conduit 122 to the bottom of the second regeneration chamber 109b; The combustion gases are then discharged through line 123. This line is equipped with a safety valve 124.

The other portion of the catalyst is transferred by conduit 126 towards a heat exchanger [32] mounted in parallel. The heat exchanger is constituted by a diaphragm tube 135 forming a sealed enclosure. These tubes 135 extend parallel to the longitudinal axis of the heat exchanger and are interconnected by longitudinally welded ribs to form an outer envelope.

The heat exchanger 132 also includes a plurality of tubes 135a regularly arranged concentrically around its axis. Water supply pipe 13
8 feeds the bottom of said inner and outer tubes, and a drain 139 drains the hot liquid from the top of the heat exchanger.

According to another embodiment of the invention not shown in FIG. 2, the lower end 133 of the heat exchanger 132 is provided with an elbow tube having second air injection means for adjusting the catalyst flow rate to the heat exchanger. 140 connects the catalyst circulation pipe 103 to the base of the riser 101.

In another embodiment illustrated in FIG.
2 can not be placed outside the catalyst regenerator. A heat exchanger is incorporated into the first regeneration section 109a. A partition wall 150 acts as a heat exchange plate, which partition wall is planar or arcuate and forms, together with the walls of the regeneration section, a heat exchange section within the regeneration section. The dimensions of the partition walls that limit the height of this heat exchanger are determined to exceed the height of the dense fluidized bed.

The regenerated hot catalyst enters the bottom of this heat exchanger from meelbo 140. Air injection means 141 condition this catalyst stream 1 entering the heat exchanger. The catalyst is fluidized at the lower end 133 of the heat exchanger by a fluidization ring 134 and cooled by circulating through the heat exchanger from bottom to top in contact with cooling pipes 135 supplied with water from line 138. . The heated water is drained through line 139. The catalyst then overflows the partition wall 150 and falls onto the dense fluidized bed 125 of the regeneration unit.

In the case of Figures 2 and 3, in order to maintain the temperature of the second regeneration unit at a sufficient level and thus the temperature of the regenerated catalyst circulated to the inlet of the riser at the specified temperature corresponding to the cracking charge. , the flow rate of the catalyst flowing through the heat exchanger is adjusted by a flow rate control means (valve 131 or air injection means 141).

The catalyst flow control means (131, 141) is controlled by the dense fluidized bed temperature measuring means 152 of the second regeneration unit 109b via the control means 151 and the connecting line 153 or 154.

If the catalyst temperature in the second regeneration unit exceeds the specified temperature, the amount of catalyst entering the heat exchanger from the second regeneration unit is increased and the catalyst flow rate is adjusted as described above. in this case,
The temperature of the first regeneration unit is reduced and more coke can be combusted in this unit.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a fluidized bed catalyst cranking device equipped with a catalyst regeneration device according to the invention, which is equipped with a heat exchanger that circulates a part of the catalyst from top to bottom; FIG. FIG. 3 is an enlarged partial cross-sectional view of another embodiment in which the heat exchanger is located inside the first regeneration chamber; FIG.

Claims (1)

[Scope of Claims] 1. A method for continuously regenerating a catalyst by fluidized bed combustion of coke deposited on the catalyst during a hydrocarbon conversion reaction, wherein about 50 to 90% of the coke is In one step, the catalyst particles are combusted in a first regeneration chamber of the fluidized bed type at a temperature T1 below about 730°C, preferably between 650 and 710°C, with the regenerated catalyst particles being substantially free from the oxygen-containing fluid. This first regeneration chamber is equipped with a device for discharging the water vapor-containing gases generated or entrained during the combustion, and has a residual amount of coke of 10 to 5
0% as a second stage in a second regeneration chamber spaced apart from the first regeneration chamber in the presence of a fluid containing more than the stoichiometric amount of oxygen for combustion, at a temperature higher than T1 and lower than or equal to 950°C; In a continuous catalyst regeneration process with combustion at a temperature T2 of preferably 910° C., the temperature T2 of the regenerated catalyst particles exiting the second regeneration chamber and circulated to the conversion reaction zone is adjusted by taking a controlled amount from the catalyst of this second regeneration chamber. By cooling it to the level of temperature T3 below T1 and introducing this cooled catalyst part into the fluidized bed of the first regeneration chamber, it is maintained at a defined temperature value corresponding to the needs of the reaction zone. A continuous catalyst regeneration method, characterized in that the combustion temperature in the first regeneration chamber is maintained at a value T1 by suitably varying the amount of oxygen-containing fluid introduced into this chamber. 2. The amount of catalyst collected from the second regeneration chamber is not more than 150% by weight, preferably in the range of 15 to 50% by weight of the catalyst circulating in the first regeneration chamber. The method described in. 3. The temperature of the cooled catalyst introduced into the first regeneration chamber is in the range of 400 to 700°C, preferably 450°C.
The method according to claim 1 or 2, characterized in that the temperature is in the range of 600°C to 600°C. 4. The increase in the flow rate of the oxidizing fluid supplied to the first regeneration chamber after the introduction of the cooled catalyst is between 1 and 50%, preferably between 10 and 20%, of the normal flow rate of this fluid without the introduction of the cooled catalyst. 4. The method according to claim 1, wherein the method is within the range of . 5. a- introducing the catalyst to be regenerated and an oxygen-containing fluid into a first regeneration chamber and causing said fluid to flow countercurrently with said catalyst from bottom to top; b- of said first regeneration chamber; Separating the gas effluent at the top and taking the partially regenerated catalyst at the bottom of the first chamber and sending it into a second regeneration chamber where it is heated at a higher temperature. carrying out a second regeneration stage; c- withdrawing a portion of the catalyst from the second chamber into a heat exchanger to cool the catalyst and recover heat; and d- a heat exchanger. 5. A method as claimed in any one of claims 1 to 4, including the step of extracting cooled catalyst from the catalyst and circulating it into a fluidized bed of the first regeneration chamber. 6. A method according to claim 5, characterized in that the fluid used for cooling the catalyst in the heat exchanger is used to strip the deactivated catalyst before its regeneration process. 7. According to any one of claims 1 to 6, characterized in that the CO/CO_2 ratio in the first combustion chamber is in the range from 0.3 to 1.5, preferably from 0.3 to 1.3. the method of. 8. A method according to any one of claims 1 to 7, characterized in that the regenerated catalyst exiting the second regeneration chamber flows by gravity from top to bottom through the heat exchanger. 9. Process according to any one of claims 1 to 7, characterized in that the regenerated catalyst leaving the second regeneration chamber flows from bottom to top through a heat exchanger. 10. In the heat exchanger, the regenerated catalyst coming from the second regeneration chamber is fluidized by injecting a gas stream at a velocity of 0.1 to 1 m/s into the heat exchanger. 10. A method according to any one of claims 1 to 9. 11. The regenerated catalyst is introduced into the bottom of the heat exchanger by means of a transfer indicating an elbow section, in which
11. A method according to claim 9, characterized in that the isothermal mass of the catalyst is maintained at a value corresponding to bubble-free fluidization by injection of the first ventilation fluid. 12. The flow rate of the regenerated catalyst introduced into the heat exchanger is regulated by a valve located upstream of the heat exchanger or by injection of a second ventilation fluid in the elbow area. 12. The method according to claim 11. 13. The flow rate of the second ventilation fluid in the elbow area is 0.
．． 13. The method according to claim 12, characterized in that the range is from 01 to 0.05 kg/s/segment cross section m^2. 14. An apparatus for continuously regenerating a deactivated catalyst by fluidized bed combustion of coke deposited on the catalyst during a hydrocarbon conversion reaction, which apparatus comprises, on the one hand, coke deposited on the catalyst; The first regeneration chamber (1
2), the first regeneration chamber comprising a deactivated catalyst introduction conduit (13) and an oxygen-containing fluid supply means (18, 20).
) and gas evacuation means (22, 24), the device also comprising on the other hand a second regeneration chamber (23);
This second regeneration chamber has a conduit (24) for introducing partially regenerated catalyst from said first chamber and a second combustion fluid supply means (25, 26) for separating the combustion gases from the regenerated catalyst. means (31), each said chamber further comprising means (16, 25) for measuring the combustion temperature of the fluidized bed.
a heat exchanger (34) and a combustion temperature in the second chamber of 950° C. or less, preferably 910° C.
means (33) for withdrawing a portion of hot catalyst from said second regeneration chamber to maintain it equal to a first specified value of °C;
Then, the hot catalyst portion is transferred to the heat exchanger (3).
4) for cooling the catalyst in the heat exchanger and discharging the catalyst cooled in the heat exchanger to the first regeneration chamber (1);
2) and the temperature in said first regeneration chamber is below 730°C, preferably between 650°C and 70°C.
In order to maintain the second specified value within the range of 10°C,
and means (19) for regulating the supply of combustion fluid controlled by temperature measuring means (16) in the regeneration chamber. 15. A valve (39) located downstream or upstream of the heat exchanger (34) is controlled by combustion temperature measuring means (25) in the second regeneration chamber (23) to 15. The device according to claim 14, characterized in that the amount of catalyst collected in ) and cooled in a heat exchanger is controlled. 16. Apparatus according to any one of claims 13 to 15, characterized in that the heat exchanger (34) comprises a fluid diffusion means (37) for maintaining the catalyst in a fluidized state within the heat exchanger (34). 17, the second regeneration chamber (23) is the first regeneration chamber (
12), in which the deactivated catalyst to be regenerated flows countercurrently to the oxidizing fluid, and the heat exchanger (34) Claim characterized in that it is arranged at an intermediate level of the chambers (12, 23), so that the hot catalyst portion which is taken up in the second regeneration chamber and transferred to the heat exchanger is moved by gravity. 17. The device according to any one of 13 to 16. 18. Device according to claim 17, characterized in that the catalyst section transverse to the heat exchanger (34) moves vertically therein. 19. Claim characterized in that it comprises transfer means (126, 128, 140) for supplying the catalyst to the bottom of the heat exchanger (137) and causing the catalyst to flow from bottom to top in the heat exchanger as a fluidized bed. The device according to item 14. 20. Said transfer means comprises an elbow part (140) in the vicinity of said heat exchanger (132), the lowermost part of which comprises at least one injection means (141) of a second venting fluid for adjusting the catalyst flow rate; 20. A device according to claim 19, characterized in that: 21. Device according to claims 13 to 21, characterized in that the heat exchanger (34, 137) is arranged outside the regeneration chamber. 22, the heat exchanger (132) has a sealed skin housing a plurality of cooling tubes along its axis, and a plurality of cooling tubes (135a) disposed along at least one concentric circle with respect to the skin for circulating cooling fluid. ) The device according to any one of claims 13 to 20, characterized in that it comprises: 23. The heat exchanger is characterized in that it has a partition wall (150) disposed inside the first regeneration chamber, having a height exceeding the dense fluidized bed of the first regeneration chamber and defining a heat exchange section. 20. A device according to any one of claims 13 to 19.